Add FAM/Gamin support to eAccelerator

[niek]

FYI: I submit this ticket per request of Bart.

I talked with Bart about FAM (or Gamin, which has the same API) support in eAccelerator. FAM allows applications to receive events if a certain files (or: files in a directory) are changed, instead of polling these files. This would be a great addition to eAccelerator, which currently features a mtime = 0 (manual cache clearing) and mtime = 1 (stat() on files) setting.

The solution we currently use is: mtime = 0 in combination with an external FAM program which monitors the web directories and invalidates the cache in case of a file change. The API of FAM is not really hard to read, and implementing it is quite straightforward, see  http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?db=man&fname=/usr/share/catman/p_man/cat3x/fam.z and  http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=0650&db=bks&fname=/SGI_Developer/books/IIDsktp_IG/sgi_html/ch08.html.

If you would like to, I could give you the source of the program we wrote, but I think the links above will do.

Thanks!